The surface of a road is deteriorated by a vehicle traffic load and the action of a natural environment. Thus, a special vehicle such as a road surface state measurement vehicle drives on a road to periodically inspect the state of a pavement on the road. As a result of the inspection, when a bump, a groove, or a crack is detected on the road surface of a road, repair of the road is performed.    Patent Literature 1: Japanese Laid-open Patent Publication No. 2001-134889
However, in the related art, there is a problem in that it is difficult to detect the deterioration of the road surface at an early stage.
That is, since the road surface state measurement vehicle is expensive and rare, it is difficult to perform the inspection of the road surface frequently. Thus, when the road surface is inspected using the road surface state measurement vehicle, it is difficult to detect the deterioration of the road surface at an early stage. As a result, detection of the deterioration of the road surface is delayed, and the cost for repair increases.